For Juvenile Moose, Momma’s Boys and Girls Fare Best

Size often matters in the animal kingdom, with larger animals faring better than their compact counterparts. But a recent WCS study suggests that for a juvenile moose, mother’s presence—not body mass—is key to survival.

If you’re a young moose trying to make it in the real world, you can’t beat an overprotective mother. While it’s true that for countless animals, from elk to fish to lizards, the bigger the baby, the better its survival odds—body size isn’t much help when it comes to orphaned moose.

A new study by WCS conservation biologist Dr. Joel Berger emphasizes the importance maternal protection plays in a young moose’s development. Berger conducted his fieldwork over the course of 10 years in the Tetons of Wyoming. He found that during their first winters, orphaned moose are subjected to as much as 47 percent more aggression from adults compared to their counterparts with mothers present.

Berger witnessed specific threats to orphaned moose—displacement from feeding areas and kicking by adult females—and theorizes that orphans incur greater metabolic costs and expend more energy in deep snow. He suspects that mothers take pains to preserve resources for their offspring, leaving orphans to fend for themselves. As a result of all these factors, orphan calves are eight times less likely to survive.

Berger’s research offers implications for how harvest quotas are set for adult moose, and he suggests the need for related policy changes. “In some circumstances, the shooting of mothers with young has been permitted under the assumption that calf survival is minimally affected,” he said. Clearly, that is not the case.”